Basic Genetics

Question 1

What is heterochromatin?

Answer 1

Heterochromatin

Question 2

Stains as light bands and consists of highly condensed regions that are usually not transcriptionally
active

Answer 2

Achromatin

Question 3

Stains as light bands and consists of highly condensed regions that are usually not transcriptionally
active

Answer 3

Eurochromatin

Question 4

Humans have a complement of 46 chromosomes arranged into23 pairs; one member of each pair is
inherited from the father and the other from the mother.Each of the members of one chromosome
pair is referred to as a autosomal homologue.

Answer 4

1st one correct: 2nd incorrect (chromosome)

Question 5

Mitosis is the process of cell division unique to gametes (ova and sperm). In contrast to meiosis, the
process of mitosis produces four gametes with genetic variability. This results in four unique, rather
than two identical, daughter cells. Meiosis is the process of replication in nucleated body cells (except ova and sperm cells).

Answer 5

Both false. Interchanged.

Question 6

During this period, the nucleolus (nucleoli) becomes visible, and the chromosomes are
extended and active metabolically. The cell synthesizes RNA and protein in preparation for
cell division.

Answer 6

G1 (Gap 1)

Question 7

This is the time of DNA replication, during which both growth and metabolic activities are
minimal.
The centrosome is also duplicated during the S stage.

Answer 7

S phase (DNA synthesis)

Question 8

Relatively short, lasting approximately 4 to 5 hours

Answer 8

G2 (Gap 2)

Question 9

Last stage of interphase.

Answer 9

G2 (Gap 2)

Question 10

Give the steps in the Mphase/ Mitosis phase in chronological order.

Answer 10

Prophase
Metaphase
Anaphase
Telophase
(PMAT)

Question 11

Sister chromatids move to the equatorial plate

Answer 11

Metaphase

Question 12

The chromatin becomes tightly coiled.
Nucleolus and nuclear envelope disintegrate.
Centrioles move to opposite poles of the cell

Answer 12

Prophase

Question 13

A segment of DNA arranged along the chromosome at a specific position called locus

Answer 13

Gene

Question 14

Total genetic composition of an individual, representing maternally and paternally derived genes. It is the
complement of DNA that is inherited.

Answer 14

Genotype

Question 15

Normal number of human chromosomes?
Autosomes?

Answer 15

46 (1 pair of 23 chromosomes from each parent)
44 autosomes (1pair of 22 chromosomes from each parent)

Question 16

State that genes for different traits are inherited separately from each other. This allows for all
possible combinations of genes to occur in the offspring

Answer 16

Law of Assortment

Question 17

Any change in the structure or sequence of DNA, whether it is physical or biochemical.

Answer 17

Mutation

Question 18

What is the simplest type of mutation, in which only one nucleotide in the DNA
sequence is changed?

Answer 18

Point mutation

Question 19

Results in a change in a codon, which alters the amino acid in the corresponding
peptide

Answer 19

Missense mutation

Question 20

results when a point change in one of the nucleotides of a DNA sequence causes one of the three possible stop codons to
be formed

Answer 20

Nonsense mutation

Question 21

Give rise to pseudogenes and other so-called junk DNA that does not code for proteins
E.g glycophorin A and B genes; the second involves the genes RHD and RHCE. The Chido and Rodgers
blood group antigens, carried on the complement components of the C4A and C4B genes.

Answer 21

Duplication

Question 22

An example of such an event resulting in a hybrid formation is seen in the MNSs blood group system.

Answer 22

Recombination

Question 23

initiation, elongation, and termination

Answer 23

Translation

Question 24

organelles composed of proteins and ribosomal RNA (rRNA)

Answer 24

Ribosomes